1. Field of the Invention
The present invention relates to an apparatus for removing substances stuck to underwater surfaces of ships or other structures, such as seaweed and shells, and for cleaning the underwater surfaces.
2. Description of the Prior Art
A conventional cleaning apparatus comprises rotary brush for use underwater and a pump for forming a water jet stream from the front side to the rear side of said rotary brush. The cleaning apparatus is usually towed by a diver so that the front side of said rotary brush abuts against the fouled surface of underwater structure and handled so as to rotate the rotary brush by actuating the pump. The front side of the rotary brush is stuck to the underwater structure owing to the jet stream formed by the driving of pump, and fouling stuck to the surface of the underwater structure is removed by the rotation of said rotary brush.
When there are spots which should not be subjected to friction with the brush during the cleaning operation by means of such cleaning apparatus, the cleaning should be removed from the surface or the rotary brush should be stopped, each time the brush reaches such a spot. Since the rotary brush and pump are driven integrally, it is very difficult to remove the cleaning apparatus from the fouled surface of the underwater structure while the rotary brush is rotating. Hence, contact of the rotary brush with such spots is avoided usually by stopping the rotation of said rotary brush. As a result, said rotary brush can be separated very easily from said spots, but the pump is also stopped by the stopping of rotary brush, so that the cleaning apparatus comes off from the fouled surface of the underwater structure, resulting in the very troublesome requirement of shifting the cleaning apparatus to the subsequent fouled surface and restoring it to the original position.
In addition, the structure surface has various types of foulings such as seaweed, shells, etc. stuck thereto under varied sticking conditions and the surface to be cleaned is not uniform, so that it is preferable to select and use a rotary brush with bristles having hardness, density, etc., suitable correspondingly to the types of fouling, how it is stuck to the surface and the condition of the surface to be cleaned.
The conventional cleaning apparatus has disadvantages that its rotary brush is not easily detachable and takes time and labour to replace the rotary brush. Further, there are insufficient types of rotary brushes available so as to be able to select the appropriate brush depending on the types of fouling, how it is stuck to the surface and the condition of the surface to be cleaned.